Light emitting device and light emitting device package having the same

Abstract

A light emitting device includes a plurality of clusters spread on a surface of a substrate and a first semiconductor layer provided over the plurality of clusters. The first semiconductor layer may includes air gaps above the plurality of clusters. In addition, light emitting structure may include a first conductive semiconductor layer adjacent to the first semiconductor layer, an active layer on the first conductive semiconductor layer, and a second conductive semiconductor layer on the active layer.

What is claimed is: 
     
       1. A light emitting device comprising:
 a substrate; 
 a plurality of clusters disposed over a surface of the substrate; 
 a first semiconductor layer disposed to contact and at least partially overlap upper surfaces of the plurality of clusters and to overlap the substrate, wherein the first semiconductor layer includes air gaps overlapping respective ones of the plurality of clusters; 
 a second semiconductor layer disposed over the first semiconductor layer and the air gaps; and 
 a light emitting structure over the second semiconductor layer, wherein the light emitting structure includes a first conductive semiconductor layer over the second semiconductor layer, an active layer over the first conductive semiconductor layer, and a second conductive semiconductor layer over the active layer, wherein the air gaps and respective ones of the plurality of clusters overlap one another along substantially vertical axes, 
 wherein the clusters comprise at least one of MgN clusters or Mg clusters. 
 
     
     
       2. The light emitting device of  claim 1 , wherein the air gaps are aligned with the clusters. 
     
     
       3. The light emitting device of  claim 1 , wherein the substrate comprises at least one of a buffer layer of at least one of Group II to VI elements, an undoped semiconductor layer or a doped semiconductor layer under the cluster layer. 
     
     
       4. The light emitting device of  claim 1 , wherein the first semiconductor layer includes at least one of an undoped semiconductor layer, a nonconductive semiconductor layer or a conductive semiconductor layer. 
     
     
       5. The light emitting device of  claim 1 , wherein each of the plurality of clusters has a size that lies in a range of about 1 Å to about 9000 Å. 
     
     
       6. The light emitting device of  claim 1 , wherein the second semiconductor layer includes a super lattice structure. 
     
     
       7. The light emitting device of  claim 1 , wherein at least one of the air gaps of the first semiconductor layer has a conical shape. 
     
     
       8. The light emitting device of  claim 1 , wherein the substrate is a conductive type substrate. 
     
     
       9. The light emitting device of  claim 1 , further comprising a first electrode coupled to the first conductive type semiconductor and a second electrode coupled to the second conductive type semiconductor. 
     
     
       10. The light emitting device of  claim 1 , wherein the air gaps are disposed between the second semiconductor layer and the plurality of clusters. 
     
     
       11. The light emitting device of  claim 1 , wherein the second semiconductor layer is in contact with the first semiconductor layer. 
     
     
       12. The light emitting device of  claim 1 , wherein the substrate is made of silicon. 
     
     
       13. The light emitting device of  claim 1 , further comprising:
 at least one of a transparent electrode layer or a reflective electrode layer over the second conductive semiconductor layer. 
 
     
     
       14. A light emitting device package having the light emitting device of  claim 1 , and having a package body and a plurality of lead electrodes on the package body. 
     
     
       15. The light emitting device package of  claim 14 , further comprising a molding member covering the light emitting device. 
     
     
       16. The light emitting device package of  claim 14 , wherein each of the plurality of clusters has a size that lies in a range of about 1 Å to about 9000 Å. 
     
     
       17. The light emitting device package of  claim 14 , wherein a maximum width of the clusters is wider than a maximum width of the air gaps. 
     
     
       18. The light emitting device of  claim 1 , wherein a first portion of the first semiconductor layer is in contact with one of the plurality of clusters and a second portion of the first semiconductor layer is in contact with the substrate. 
     
     
       19. The light emitting device of  claim 1 , wherein each air gap is tapered by increasing width from a lower portion closer to the substrate to an upper portion closer to the second semiconductor layer. 
     
     
       20. The light emitting device of  claim 1 , wherein a maximum width of the clusters is wider than a maximum width of the air gaps.